1. Field of the Invention
The present invention relates to an RF (Radio Frequency) nanoswitch allowing the passage of a high frequency signal.
2. Description of the Related Art
Recently, according to development of a MEMS (Micro Electro Mechanical Systems) technique, MEMS RF nanoswitches have been developed, and in addition, nanometer-sized RF nanoswitches are on the way of being developed.
FIG. 1 schematically shows a conventional nanometer-sized subminiature RF nanoswitch, wherein the RF nanoswitch comprises a driving power supply 10, a source 20 connected one terminal of the power supply 10, at least one conductive nanotube 30 supported to be capable of being electrically connected to the source 20, a gate 40 provided under the nanotube 30 and connected to the other terminal of the driving power supply 10 to generate an electrostatic attractive force in cooperation with the nanotube 30, and a drain 50 in contact with the nanotube deformed by the electrostatic attractive force.
The RF nanoswitch having the aforementioned features is operated as follows. At first, if a controller, not shown in the drawing, applies a power to the driving power supply 10, an electrostatic attractive force is produced between the gate 40 and the nanotube 30 and thus the nanotube 30 sinks as indicated by dotted lines in FIG. 1. In addition, the sinking nanotube 30 comes into contact with the drain 50, whereby the RF nanoswitch is turned ON. In the ON state of the RF nanoswitch, an RF signal is inputted through the source and transmitted to a desired place through the nanotube 30 and the drain 50. Whereas, if no power is applied to the driving power supply 10, the nanotube 30 and the drain 50 are electrically isolated from each other and an RF signal cannot be transmitted to the drain 50.
However, the RF nanoswitch having the above-mentioned feature generates electric resistance of several tens to several hundreds kΩ at a contact portion between the nanotube 30 and the drain 50. Due to such electric resistance, an RF signal cannot be transmitted to the drain even if the RF nanoswitch is in the ON state or an increased loss in RF signal is caused even if the RF signal is transmitted. Accordingly, it is substantially difficult to commercialize such an RF nanoswitch as shown in FIG. 1.